Clinical StudyElderly Patients with Moderate Chronic Ischemic MitralRegurgitation: Coronary Artery Bypass Grafting Alone orConcomitant Mitral Annuloplasty?

Qiang Ji,1 Yun Zhao,2 JinQiang Shen,1 YuLinWang,1 Ye Yang,1 LiMin Xia,1,3 Kai Song ,1,3

and ChunSheng Wang 2

1Department of Cardiovascular Surgery of Zhongshan Hospital Fudan University, Shanghai 180 Fenglin Road,Shanghai 200032, China2Shanghai Institute of Cardiovascular Diseases, 1609 Xietu Road, Shanghai 200032, China3Department of Cardiovascular Surgery of Xiamen Branch of Zhongshan Hospital Fudan University, 668 Jinhu Road,Huli District, Xiamen 510530, China

Correspondence should be addressed to Kai Song; 824105863@qq.com and ChunSheng Wang; zscardiacs2016@163.com

Received 20 April 2019; Revised 29 October 2019; Accepted 25 November 2019; Published 18 December 2019

Academic Editor: Elena Cavarretta

Copyright © 2019Qiang Ji et al./is is an open access article distributed under the Creative Commons Attribution License, whichpermits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Background. An increasing number of elderly patients with ischemic mitral regurgitation (IMR) are referred for coronaryartery bypass grafting (CABG). However, data about the management of elderly patients with moderate IMR are scanty. /isstudy evaluates the impacts of two surgical approaches (CABG alone or concomitant mitral annuloplasty (MAP)) on in-hospital and midterm outcomes, to attempt to determine an appropriate treatment option for elderly patients with moderatechronic IMR. Methods. All eligible patients over 65 years of age were included and were entered into either a MAP group(patients undergoing CABG plus MAP, n � 96) or a CABG group (patients receiving CABG alone, n � 104). Baseline andsurgical characteristics were analyzed, and in-hospital and midterm outcomes between groups were compared after pro-pensity score-matching (1 : 1). Results. Using propensity score-matching, 82 pairs of patients were successfully established in a1 : 1 ratio. No significant differences between the two matched groups were found regarding surgical mortality (4.9% vs. 1.2%,p � 0.173) and major postoperative morbidity. 150 patients (76 in the MAP group and 74 in the CABG group) receivedregular follow-up visit with the median duration of 37 months. Compared with the CABG group, the MAP group received asimilar overall survival but a better recurrent MR-free survival (stratified log-rank p, 0.492 and < 0.001, respectively). UsingCox regression, the MAP group as compared with the CABG group did not affect midterm survival probability (propensityscore-adjusted hazard ratio, 0.854; 95% confidence interval, 0.571–2.729, p � 0.630). Additionally, patients in the MAP grouphad a significantly lower ratio of NYHA class III-IV at the latest follow-up by comparison with patients in the CABG group(19.7% vs. 35.5%, p � 0.033). Conclusion. Compared with CABG alone, concomitant mitral annuloplasty is associated withimproved midterm outcomes (including reduced IMR recurrence and improved cardiac functional class) but shares similarsurgical mortality and major postoperative morbidity and may be a promising treatment option for elderly patients withmoderate chronic IMR.

1. Introduction

With the acceleration of population aging, the advancementof surgical techniques, and the improvements in peri-operative management, the current coronary artery bypassgrafting (CABG) population has seen increased pre-ponderances of aging and concomitant disease related to

coronary artery disease [1–3]. Age is a risk factor for poorprognosis following surgical revascularization [4]. Com-pared with the young, elderly patients have a higher burdenof surgical risk factors with reduced functional capacity andincreased comorbidity conditions [5].

/e development of ischemic mitral regurgitation (IMR)is associated with an increased risk of heart failure and

HindawiCardiology Research and PracticeVolume 2019, Article ID 1846904, 8 pageshttps://doi.org/10.1155/2019/1846904

mortality, and this risk increases with the severity of mitralregurgitation (MR) [6]. /e optimal management of mod-erate chronic IMR (mitral valve procedure at the time ofCABG or CABG alone) remains controversial. AlthoughIMR recurrence occurs at follow-up, the mitral valve pro-cedure at the time of CABG does reduce MR after surgery[7–12]. Although it may reduce MR at follow-up, CABGalone is not sufficient to eliminate MR [3].

Our previous study supported the concomitant mitralvalve procedure instead of CABG alone for the treatment ofmoderate chronic IMR [13]. However, the subjects of ourprevious study included not just the elderly but the non-elderly. Given the increasing number of elderly patients withmoderate chronic IMR referred for surgical re-vascularization, there is a need to determine which surgicalapproach (concomitant mitral valve procedure or CABGalone) is an appropriate treatment option for elderly patientswith moderate chronic IMR. Unfortunately, the data aboutthe management of elderly patients with moderate chronicIMR are scanty.

/is study reviewed 200 elderly patients with moderatechronic IMR who underwent either CABG plus mitralannuloplasty or CABG alone in our institute and evaluatedthe impacts of the two surgical approaches on in-hospitaland midterm outcomes, to attempt to determine an ap-propriate treatment option for elderly patients with mod-erate chronic IMR.

2. Methods

2.1. Study Protocol. /is study protocol was approved by theEthics Committee of Zhongshan Hospital Fudan University(no. B2018-118) and was consistent with the Declaration ofHelsinki.

/e etiology and severity of MR were determined bytransthoracic echocardiography within 3 days before sur-gery. MR grade was defined as moderate (effective regur-gitant orifice area <20mm2, regurgitant volume< 30ml, andregurgitant fraction< 50%) according to the literature [14].MR was graded independently by two level 3 readers (dis-crepancies were resolved by a third reader as needed) assuggested by current guidelines with an integrated approachusing all available parameters.

Consecutive patients over 65 years of age with moderatechronic IMR who underwent CABG plus mitral valve repairor CABG alone during the study period (from June 2010 toJune 2017) were assessed for study eligibility by checking thefollowing criteria: (1) prior myocardial infarction by elec-trocardiogram or regional wall motion abnormalities byechocardiography; (2) structurally normal mitral valve; and(3) sinus rhythm. Exclusion criteria were moderate or severeaortic stenosis or insufficiency, concomitant tricuspidannuloplasty, mitral valve organic pathology (prolapse,rheumatic, endocarditis, leaflet perforation, or extensiveannular calcification), valve prosthesis, Marfan’s syndrome,and unstable clinical conditions. Considering that patientsundergoing complex mitral valve repair may not receivesimilar outcomes as patients undergoingmitral annuloplastyalone, patients who underwent concomitant leaflet and/or

subvalvular procedure (including edge-to-edge, leafletaugmentation, secondary chordal cutting, and papillarymuscle approximation) were excluded and patients whoreceived mitral annuloplasty alone at the time of CABGwereincluded. Additionally, considering that on-pump CABGalone accounted for less than 5% of CABG alone in ourcenter and isolated off-pump CABG may not result insimilar outcomes (especially in-hospital outcomes) as on-pump CABG alone, patients undergoing on-pump CABGalone or urgent conversion from off-pump to on-pumpCABG during surgery were also excluded and patients re-ceiving off-pump CABG alone were included.

All of the included patients were entered into a MAPgroup or a CABG group. Patients in theMAP group receivedmitral annuloplasty at the time of CABG aided by cardio-pulmonary bypass, whereas those in the CABG group un-derwent off-pump CABG alone. Patients were regularlyfollowed up at 3 and 6 months following surgery andthereafter at 6-month intervals. If patients developedsymptoms or doubtful symptoms of MR or coronary arterydisease at follow-up, clinic visits should be performed at thetime.

Perioperative data were obtained from our institutionaldatabase and were reviewed using a standard data collectionform. Follow-up data were obtained by clinic visit and/ortelephone. Data collection was performed by trained staff(two people). /e trained staff, however, were not informedof the purpose of this study. To reduce the effects oftreatment selection bias and potential confounding, pro-pensity score-matching (1 :1) was used to adjust for dif-ferences in baseline characteristics. In-hospital and follow-up outcomes were compared between the two matchedgroups.

2.2. Outcomes. In-hospital outcomes consisted of surgicalmortality and major postoperative morbidity. Major post-operative morbidity included myocardial infarction asso-ciated with CABG, low cardiac output, redo for bleeding,prolonged ventilation of more than 24 hours, stroke, renalfailure requiring hemodialysis, and deep sternal woundinfection. /e definitions of surgical mortality and majorpostoperative morbidity referred to previous studies [15, 16].Additionally, intra-aortic balloon pump (IABP) support,drainage during the first 24 h following surgery, bloodtransfusion, length of intensive care unit (ICU) stay, andlength of postoperative hospital stay were also recorded.

Follow-up outcomes included all-cause death and IMRrecurrence. All-cause mortality rather than cardiac mortalitywas chosen because it was the most robust and unbiasedindex which exempted us from misreading the cause ofdeath with the subjective and sometimes inaccurate medicalrecords. /e occurrence of moderate or more MR de-termined by transthoracic echocardiography at follow-upwas diagnosed as IMR recurrence. Additionally, cardiacfunction class (NYHA III-IV) was also recorded.

2.3. Surgical Procedures. In our institute, off-pump CABGsurgery was introduced in 1998 and has been the first choice

2 Cardiology Research and Practice

in patients who were referred for surgical revascularizationalone over the years with an annual procedure volume ofover 500 cases, whereas on-pump CABG was conducted inpatients with severely impaired left ventricular function,deeply intramyocardial target vessels, previous cardiacsurgery, or concomitant open-heart surgery. /e decision toperform CABG alone or concomitant mitral annuloplastywas influenced by each patient’s demographic and clinicalprofile (i.e., age, comorbidities such as chronic obstructivepulmonary disease and renal dysfunction, left ventricularendodiastolic diameter, and estimated surgical risks), but thechoice was ultimately left to the discretion of the operatingsurgeon. All the procedures (either CABG alone or con-comitant mitral annuloplasty) were performed by the samesurgical team.

All surgical procedures were performed through amidline sternotomy. /e internal mammary artery washarvested in a skeletonized or a pedicled fashion, and the leftinternal mammary artery grafting to the left anteriordescending artery has been the first choice. Saphenous veinand radial artery were harvested with an open technique, andsequential or separate aortocoronary bypass grafting wasperformed in the remaining coronary arteries. /e quality ofanastomosis was assessed after grafting with a transit-timeflow probe (Medistim Butterfly Flowmeter, Oslo, Norway)during the operation. /e details of the off-pump and on-pump CABG procedures were consistent with those ofprevious studies [17, 18].

/e mitral valve was exposed through a vertical trans-septal approach along the right border of the foramen ovale,leaving the left atrial roof untouched./e size of the ring wasdetermined after careful measurement of the height of theanterior leaflet and then downsizing. All included patientsunderwent mitral annuloplasty with a downsized rigidcomplete-ring (Edwards Physio rigid complete-ring). Ringswere inserted using deep U-shaped simple horizontal su-tures using Ethibond 2-0 (Ethicon, Inc, Somerville, NJ) orTi-Cron 2-0 (Syneture, Norwalk, CT). /e quality of mitralrepair was determined by intraoperative transesophagealechocardiography immediately after discontinuation ofcardiopulmonary bypass.

2.4. Statistics Analysis. Normally distributed continuousvariables were expressed as the mean± standard deviation,and nonnormally distributed continuous variables wereexpressed as median and interquartile range (IQR). Cate-gorical variables were expressed as frequency distributionsand single percentages. To control for measured potentialconfounders in the dataset, a propensity score (PS) wasgenerated for each patient from a multivariable logisticregression model that was based on 19 characteristics (aslisted in Table 1, including demographics variables, con-comitant diseases, preoperative cardiac status variables, andnumber of grafts) as independent variables with surgicalapproach (CABG plus mitral annuloplasty vs. off-pumpCABG alone) as a binary dependent variable. /e dis-crimination power and calibration of the PS model weretested with the c-statistic and the Hosmer–Lemeshow

goodness-of-fit. Two pairs of matched patients were ob-tained using the greedy-matching algorithm to implementnearest-neighbor 1 :1, with a caliper width of 0.2 of standarddeviation of the logit of the PS. /e quality of the match wasassessed by comparing selected pretreatment variables inpropensity score-matched patients using the standardizedmean difference.

Normally distributed continuous variables were com-pared between groups using Student’s t-test beforematching and paired t test after matching. Nonnormallydistributed continuous variables were compared betweengroups with the Wilcoxon rank-sum test before and aftermatching. Categorical variables were compared betweengroups using χ2 test or Fisher’s exact test (when appro-priate) before matching and McNemar’s test aftermatching. For the analysis of in-hospital outcomes in thematched population, McNemar’s test with odds ratios (OR)and 95% confidence interval (CI) was used for categoricaloutcomes. /e impacts of surgical approach (CABG plusmitral annuloplasty vs. off-pump CABG alone) as in-dependent risk factors on surgical mortality and majorpostoperative morbidity were evaluated using conditionallogistic regression analysis. Overall survival and recurrentIMR-free survival were estimated using the Kaplan–Meiermethod with the stratified log-rank test to compare theequality of the survival curves in the PS-matched pop-ulation. /e Cox regression model stratified on thematched pairs was used to estimate the PS-adjusted hazardratio (HR) and 95% CI of midterm survival probabilitybetween the two matched groups. A two-sided p value lessthan 0.05 was considered statistically significant. Statisticalanalysis was performed with SPSS statistical package ver-sion 22.0 (SPSS Inc., Chicago, IL, USA).

3. Results

3.1. Study Population. A total of 4678 consecutive patientsunderwent CABG alone (3973 patients, including 3845 off-pump CABG patients and 128 on-pump CABG patients) orconcomitant open-heart surgery (705 patients) in our in-stitute from June 2010 to June 2017. Of them, 232 patientsover 65 of age who met the inclusion criteria were reviewed.As shown in Figure 1, 32 patients were excluded, which left200 eligible patients for data analysis. Among 200 includedpatients, 96 patients who underwent mitral annuloplasty atthe time of CABGwere entered into theMAP group, and theremaining 104 patients who received isolated off-pumpCABG were entered into the CABG group.

3.2. Baseline and Procedure Characteristics. Baseline char-acteristics are shown in Table 1. Patients in the MAP group ascompared with the CABG group were younger (73.5±2.2 yearsvs. 74.4±2.6 years, p � 0.009) and had lower left ventricularejection fraction but higher left ventricular endodiastolic di-ameter (0.43±0.14 vs. 0.47±0.13,p � 0.037, and 59.2±6.6mmvs. 56.8±6.0mm, p � 0.008, respectively). In addition, com-pared with the CABG group, the MAP group had a greatereffective regurgitant orifice area (p � 0.016).

Cardiology Research and Practice 3

Table 1: Baseline and procedure characteristics.

Unmatched population Matched populationMAP group CABG group

pMAP group CABG group

p(n� 96) (n� 104) (n� 82) (n� 82)DemographicsAge (years) 73.5± 2.2 74.4± 2.6 0.009 73.8± 2.2 74.2± 2.5 0.278Gender (female) 16 (16.7%) 23 (22.1%) 0.331 14 (17.1%) 17 (20.7%) 0.720Obesity 12 (12.5%) 15 (14.4%) 0.691 10 (12.2%) 12 (14.6%) 0.832Smoking history 38 (39.6%) 39 (37.5%) 0.762 33 (40.2%) 32 (39.0%) 0.873

Concomitant diseasesHypertension 64 (66.7%) 65 (62.5%) 0.538 54 (65.9%) 52 (63.4%) 0.923Diabetes mellitus 35 (36.5%) 43 (41.3%) 0.479 31 (37.8%) 34 (41.5%) 0.804Hyperlipidemia 23 (24.0%) 29 (27.9%) 0.527 20 (24.4%) 23 (28.0%) 0.761COPD 11 (11.5%) 14 (13.5%) 0.757 10 (12.2%) 11 (13.4%) 0.815Prior CVA 8 (8.3%) 12 (11.5%) 0.450 7 (8.5%) 9 (11.0%) 0.804CKD 9 (9.4%) 12 (11.5%) 0.618 8 (9.8%) 9 (11.0%) 0.798

Preoperative cardiac statusPrevious PCI 22 (22.9%) 28 (26.9%) 0.513 19 (23.2%) 21 (25.6%) 0.875Recent MI 43 (44.8%) 37 (35.6%) 0.184 38 (46.3%) 32 (39.0%) 0.550NYHA III-IV 27 (28.1%) 21 (20.2%) 0.189 23 (28.0%) 18 (22.0%) 0.533LVEF 0.43± 0.14 0.47± 0.13 0.037 0.44± 0.15 0.46± 0.14 0.379LVEDD (mm) 59.2± 6.6 56.8± 6.0 0.008 58.7± 6.5 57.9± 6.1 0.418ERO (mm2) 17 (13–18) 15 (11–17) 0.016 17 (13–18) 16 (12–17) 0.158

Extent of CAD2-vessel 14 (14.6%) 13 (12.5%) 0.667 10 (12.2%) 9 (11.0%) 0.8073-vessel 82 (85.4%) 91 (87.5%) 72 (87.8%) 73 (89.0%)LM 30 (31.3%) 32 (30.8%) 0.941 26 (31.7%) 27 (32.9%) 0.867

Surgical dataOn-pump 96 (100%) 0 80 (100%) 0CPB time (min) 95.9± 21.4 0 96.0± 21.4 0ACC time (min) 78.5± 13.7 0 79.5± 13.8 0Number of grafts 3 (3, 3) 3 (3, 3) 0.531 3 (3, 3) 3 (3, 3) 0.724Use of left IMA 95 (99.0%) 103 (99.0%) 0.955 81 (98.8%) 82 (100%) 0.316Use of right IMA 0 5 (4.8%) 0.030 0 3 (3.7%) 0.080Use of vein graft 94 (97.9%) 100 (96.2%) 0.465 81 (98.8%) 80 (97.6%) 0.560Use of RA 3 (3.1%) 5 (4.8%) 0.723 3 (3.7%) 4 (4.9%) 1.000

MAP group, patients undergoing combined CABG and mitral annuloplasty; CABG group, patients undergoing off-pump CABG alone. BMI, body massindex; COPD, chronic obstructive pulmonary disease; CVA, cerebrovascular accident; CKD, chronic kidney disease; PCI, percutaneous coronary in-tervention; MI, myocardial infarction; AF, atrial fibrillation; NYHA, New York Heart Association; LVEF, left ventricular ejection fraction; LVD, leftventricular dysfunction; LVEDD, left ventricular endodiastolic diameter; LV, left ventricle; ERO, effective regurgitant orifice area; CAD, coronary arterydisease; LM, left main trunk disease; CPB, cardiopulmonary bypass; ACC, aortic cross-clamping; IMA, internal mammary artery; RA, radial artery.Definition: obesity: body mass index of more than 30 kg/m2; recent MI: evidence of myocardial infarction within the last 30 days before surgery.

4678 CABG patients (June 2010–June 2017)

705 patientsCABG plus open heart surgery

3973 patientsCABG alone

126 patientsCABG plus mitral valve procedure

106 patientsCABG alone

Leaflet and/or subvalvular procedure (22)Nonischemic mitral valve prolapse (3)Aortic stenosis or insufficiency (2)Endocarditis or leaflet perforation (2)Tricuspid annuloplasty (1)

On pump CABG alone (22)Conversion from off- to on-pump (1)

MAP group: 96 patientsCABG plus mitral annuloplasty

CABG group: 104 patientsOffpump CABG alone

(i)(ii) Suffering from moderate IMR

Age over 65(i)(ii) Suffering from moderate IMR

Age over 65

(i)(ii)

(iii)(iv)(v)

(i)(ii)

Figure 1: Flowchart of selected patients. CABG, coronary artery bypass grafting; MAP, mitral annuloplasty.

4 Cardiology Research and Practice

Characteristics of surgical revascularization are alsoshown in Table 1. All patients in theMAP group received on-pump technique, with mean cardiopulmonary bypass timeof 95.9± 21.4 minutes and mean aortic cross-clamping timeof 78.5± 13.7 minutes, whereas all patients in the CABGgroup underwent isolated CABG procedure without car-diopulmonary bypass. Patients in both groups receivedsimilar number of grafts (p � 0.531).

In the MAP group, all patients received restrictive mitralannuloplasty with downsized rigid complete-rings (mediansize of 28mm) in addition to CABG. Immediately afterrepair, transesophageal echocardiography showed no ortrace MR in 88 patients (91.7%) and mild MR in 8 patients(8.3%), respectively. Transmitral pressure gradient of morethan 5mmHg was not found immediately after mitralannuloplasty.

3.3. Propensity Score-Matched Cohort. Bivariate analyseswere conducted to examine differences in baseline charac-teristics between patients in the MAP group (n� 96) andthose in the CABG group (n� 104). Propensity scores werethen calculated using a multivariate logistic regressionmodel based on the predefined 19 variables. /e Hosmer–Lemeshow goodness for the model was 4.93 (p � 0.726).Also, the model achieved good discrimination power withthe receiver operating curve resulting in the area under thecurve of 0.70 (95% CI, 0.61–0.80, p � 0.027). Finally, 82 pairsof patients were successfully established in a 1 :1 ratio. Asshown in Figure 2, all the absolute standardized differencesafter matching were <10%, indicating an adequate balance.

As shown in Table 1, the two matched groups werecomparable for baseline variables (including demographicsvariables, concomitant diseases, and preoperative cardiacstatus variables). Additionally, no significant differenceswere found between the two matched groups regardingsurgical characteristics.

3.4. In-Hospital Outcomes in the Matched Population. Nosignificant difference was found in surgical mortality be-tween the twomatched groups (4.9% vs. 1.2%, p � 0.173). Asshown in Table 2, there were no significant differencesbetween the two matched groups regarding major post-operative morbidity, including MI associated with CABG,low cardiac output, prolonged ventilation, stroke, renalfailure requiring hemodialysis, and deep sternal woundinfection. No permanent neurological impairment wasobserved. Although the MAP group as compared with theCABG group had more drainage during the first post-operative 24 h and a higher ratio of blood transfusion(438± 93ml vs. 261± 68ml, p< 0.001, and 74.4% vs. 25.6%,p< 0.001, respectively), the two groups received a similarincidence of redo for bleeding (3.7% vs. 1.2%, p � 0.620).Additionally, patients in the MAP group experienced alonger duration of ICU stay and longer length of post-operative hospital stay by comparison with patients in theCABG group.

/e impacts of surgical approach (CABG plus mitralannuloplasty vs. off-pump CABG alone) on surgical

mortality and major postoperative morbidity are shown inTable 2. Using conditional logistic regression analysis,surgical approach was not an independent risk factor forsurgical mortality or major postoperative morbidity.

3.5. Follow-Up Outcomes in the Matched Population. A totalof 150 patients (76 in the MAP group and 74 in the CABGgroup) received regular follow-up visit with a median du-ration of 37 months. Ten patients (4 in the MAP group and 6in the CABG group) died during follow-up, with the cardiacmortality of 2.6% for the matched MAP group (n� 2) and4.1% for the matched CABG group (n� 3). As shown inFigure 3, there was no significant difference between the twomatched groups regarding overall survival (χ2 � 0.473,stratified log-rank p � 0.492). Follow-up death among thematched population was modeled using Cox regression(Figure 4). /e result showed that compared with off-pumpCABG alone, CABG plus mitral annuloplasty was not as-sociated with midterm survival probability (PS-adjusted HR,0.854; 95% CI, 0.571–2.729, p � 0.630). IMR recurrenceoccurred in 62 patients during follow-up (16 in the MAPgroup and 46 in the CABG group). As shown in Figure 5,Kaplan–Meier curves showed the MAP group as comparedwith the CABG group received a better recurrent MR-freesurvival (χ2 �15.721, stratified log-rank p< 0.001).

PrematchPostmatch

Number of gra�s

Le� main artery disease

Double/triple vessel disease

Effective regurgitant orifice area

Le� ventricular endodiastolic diameter

Le� ventricular ejection fraction < 40%

NYHA class III-IV

Recent myocardial infarction

Previous percutaneous coronary intervention

Chronic kidney disease

Prior cerebrovascular accident

Hyperlipidemia

Chronic obstructive pulmonary disease

Diabetes mellitus

Hypertension

Recent smoking

Obesity

Gender

Age

10 20 30 400

Absolute standardized difference (%)

Figure 2: Absolute standardized differences for baseline covariatesbefore and after matching. NYHA, New York Heart AssociationFunctional Classification.

Cardiology Research and Practice 5

Additionally, patients in the MAP group had a significantlylower ratio of NYHA class III-IV at the latest follow-up bycomparison with patients in the CABG group (19.7% vs.35.5%, p � 0.033).

4. Discussion

/e results of midterm follow-up showed that although nobenefit for midterm survival was observed, concomitantmitral annuloplasty as compared with CABG alone in thetreatment of elderly patients with moderate chronic IMRreceived improved cardiac functional class and reduced IMRrecurrence. In this study, CABG plus mitral annuloplasty ascompared with off-pump CABG alone had a significantlylower ratio of NYHA class III-IV at the latest follow-up./isresult suggested a significant benefit for midterm cardiacfunctional class after CABG plus mitral annuloplastycompared with CABG alone. Chan and colleagues [7] haveconducted a prospective observational study (RIME trial)

comparing CABG plus mitral valve procedure vs. CABGalone for 73 patients referred for CABG with moderate IMRand have reported an improved functional capacity with theCABG plus mitral valve procedure group. /is evidence wasconsistent with our finding. Our finding was contradicted bythe observations of Smith and colleagues [12], who reportedsimilar improvement in functional capacity. /is studyshowed that patients in the MAP group received a betterrecurrent MR-free survival by comparison with patients inthe CABG group. A significant reduction of IMR recurrencemay be an intuitive finding given patients in the MAP group

Table 2: In-hospital outcomes in the matched population.

Outcomes MAP group (n� 82) CABG group (n� 82)Univariate analysis Multivariate analysis

OR (95% CI) p OR (95% CI) p

Surgical mortality 4 (4.9%) 1 (1.2%) 3.514 (0.754–8.291) 0.173 2.821 (0.883–6.214) 0.131Major postoperative morbidityMI associated with CABG 1 (1.2%) 3 (3.7%) 0.425 (0.133–3.192) 0.311 0.618 (0.393–3.691) 0.364Low cardiac output 7 (8.5%) 2 (2.4%) 3.733 (0.852–7.542) 0.167 2.873 (0.879–5.782) 0.106Redo for bleeding 3 (3.7%) 1 (1.2%) 2.706 (0.713–6.203) 0.620 2.085 (0.816–5.737) 0.381Prolonged ventilation 10 (12.2%) 5 (6.1%) 2.139 (0.697–5.659) 0.176 1.753 (0.789–5.732) 0.138Stroke 4 (4.9%) 2 (2.4%) 2.051 (0.635–6.522) 0.682 1.573 (0.756–4.605) 0.405RF requiring hemodialysis 3 (3.7%) 1 (1.2%) 3.076 (0.613–8.203) 0.620 2.332 (0.804–6.563) 0.239DSWI 2 (2.4%) 1 (1.2%) 2.025 (0.780–5.817) 1.000 1.516 (0.803–5.528) 0.863

Other outcomesIABP support 6 (7.3%) 2 (2.4%) 3.158 (0.781–7.311) 0.277Blood transfusion 61 (74.4%) 21 (25.6%) 3.838 (2.185–8.513) <0.001Drainage during 1st 24 h (ml) 438± 93 261± 68 <0.001Length of ICU stay (h) 28.4± 7.5 17.5± 5.3 <0.001Postoperative hospitalized days 6.8± 1.8 5.5± 1.3 <0.001

OR, odds ratio; CI, confidence interval; MI, myocardial infarction; CABG, coronary artery bypass grafting; RF, renal failure; DSWI, deep sternal woundinfection; IABP, intra-aortic balloon pump; ICU, intensive care unit.

χ2 = 0.473

CABG plus MAPOff-pump CABG alone

Patients at risk:(CABG plus MAP)76

74

43

49

31

28

9

13

4

4 (Off-pump CABG alone)

Stratified log-rank p = 0.492

0.0

0.2

0.4

0.6

0.8

1.0

Cum

ulat

ive s

urvi

val

7050 60100 4020 30Months

Figure 3: Kaplan–Meier analysis for overall survival in thematched population. CABG, coronary artery bypass grafting; MAP,mitral annuloplasty.

PS-adjusted HR 0.854, 95% CI: 0.571–2.729

p = 0.630

0.0

0.2

0.4

0.6

0.8

1.0Su

rviv

al p

roba

bilit

y

20 3010 400 6050 70Months

CABG plus MAPOff-pump CABG alone

Figure 4: Survival probability using PS-adjusted Cox regressionanalysis. PS, propensity score; HR, hazard ratio; CI, confidenceinterval.

6 Cardiology Research and Practice

undergoing mitral annuloplasty at the time of CABG. /isresult was in line with the evidence from previous studies[6–8]. Additionally, this study showed that the two surgicalapproaches received a similar overall survival, and CABGplus mitral annuloplasty as compared with off-pump CABGalone was not associated with midterm survival probabilityvia Cox regression, suggesting that no benefit for midtermsurvival following concomitant mitral annuloplasty com-pared with CABG alone was observed./is result was in linewith the evidence from previous studies [3, 6–8, 10–12].

Another important finding of this study is that comparedwith off-pump CABG alone, CABG plus mitral annuloplastyin the treatment of elderly patients with moderate chronicIMR received similar surgical mortality and major post-operative morbidity. Under the condition of comparablebaseline characteristics and number of grafts, there were nosignificant differences between groups regarding surgicalmortality and major postoperative morbidity. /ese resultswere further confirmed via multivariable logistic regression.So, our results suggested that compared with CABG alone,concomitant mitral annuloplasty did not bring about morein-hospital adverse events. Few studies have evaluated theimpacts of CABG alone vs. concomitant mitral valve repairon in-hospital outcomes of elderly patients with moderatechronic IMR. A previous study [19], which compared theoutcomes of 150 elderly patients with moderate IMR whounderwent either off-pump CABG alone or CABG plusmitral valve procedure, has revealed that off-pump CABGgroup had statistically significant better early operativeoutcomes. /is evidence was not in line with our study. /ereason for this difference may have been the study pop-ulation, regarding that elder patients who were included inthis study had better left ventricular function and small leftventricular volume.

Despite similar incidence of in-hospital adverse events,the MAP group as compared with the CABG group receivedmore drainage during the first postoperative 24 h, a higherratio of blood transfusion, and longer length of ICU stay andpostoperative hospital stay, suggesting patients undergoingCABG plus mitral annuloplasty received greater trauma and

required longer duration of recovery by comparison withthose undergoing off-pump CABG alone. /is may beclosely related to the use of cardiopulmonary bypass withcardiac arrest and prolonged operative time.

Results of this study showed that for treatment of elderlypatients with moderate chronic IMR, concomitant mitralannuloplasty as compared with CABG alone reduced IMRrecurrence and improved cardiac function and thus im-proved midterm outcomes. Also, concomitant mitralannuloplasty as compared with CABG alone received similarsurgical mortality and major postoperative morbidity,suggesting concomitant mitral annuloplasty did not bringabout more in-hospital adverse events. Due to the use ofcardiopulmonary bypass with cardiac arrest and prolongedoperative time, CABG plus mitral annuloplasty as comparedwith off-pump CABG alone may bring greater trauma andlengthen the duration of recovery, but did not significantlyincrease the incidence of in-hospital adverse events./erefore, improved midterm outcomes coincided withsimilar surgical mortality and major postoperative mor-bidity, which may be in favor of CABG plus mitral annu-loplasty as a promising treatment option for elderly patientswith moderate chronic IMR.

/ere were several limitations to this study. First, it wasonly a single-center observational study involving a smallsample size, which may influence the generalizability of itsresults. Also, this study showed that the incidence of adverseevents was very low in both groups and also showed that nosignificant differences were found between the two ap-proaches regarding surgical mortality and major post-operative morbidity, which may be related to a small samplesize. A final determination would need a prospective,multicenter study involving a larger sample size. Second, allof the included patients in this retrospective study were notrandomized into CABG plus mitral annuloplasty group oroff-pump CABG alone group, which was associated withselection biases and influence on the interpretation of re-sults. Although using propensity score-matching, confoundsand selection biases among the two groups cannot beeliminated. /ird, patients who underwent concomitantleaflet and/or subvalvular procedure were excluded fromdata analysis. Patients with complex mitral valve repair ascompared with those with annuloplasty alone may receivemore midterm benefits, which may be more likely to favorCABG plus mitral valve procedure as a promising treatmentoption for elderly patients with moderate chronic IMR.Finally, the duration of follow-up was relatively short. Al-though CABG plus mitral valve procedure was supported byour data for the treatment of moderate chronic IMR inelderly patients, further studies were warranted to sub-stantiate and validate the evidence.

5. Conclusions

Compared with CABG alone, concomitant mitral annulo-plasty is associated with improved midterm outcomes (in-cluding improved cardiac functional class and reduced IMRrecurrence) but shares similar surgical mortality and major

CABG plus MAPOff-pump CABG alone

Stratified log-rank p < 0.001

Patients at risk:(CABG plus MAP)76

745449

3428

2413

144 (Off-pump CABG alone)

χ2 = 15.721

0.0

0.2

0.4

0.6

0.8

1.0

Recu

rren

t MR-

free s

urvi

val

10 20 30 40 50 60 700Months

Figure 5: Kaplan–Meier analysis for recurrent IMR-free survival inthe matched population.

Cardiology Research and Practice 7

postoperative morbidity and may be a promising treatmentoption for elderly patients with moderate chronic IMR.

Data Availability

/e data used to support the findings of this study areavailable from the corresponding author upon request.

Disclosure

Q. Ji and Y. Zhao are co-first authors.

Conflicts of Interest

/e authors report no conflicts of interest in this work.

Authors’ Contributions

C. Wang and K. Song were involved in conception anddesign. C. Wang provided administrative support. Q. Ji, Y.Zhao, J. Shen, Y. Wang, and Y. Yang provided provision ofstudy materials or patients. Q. Ji, Y. Zhao, Y. Yang, and L.Xia collected and assembled the data. Q. Ji, Y. Zhao, J. Shen,Y. Wang, and L. Xia performed data analysis and in-terpretation. All authors wrote the manuscript and approvedthe final manuscript. Q. Ji and Y. Zhao contributed equallyto this work.

Acknowledgments

/is study was partly supported by the National NaturalScience Foundation of China (Project no. 81770341).

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